In forming power or signal distribution systems it is necessary to provide interconnection between various members or components of the system. Typically the interconnections are provided by electrical connectors having one or more electrical contact terminals therein. Frequently the electrical terminals will be of the barrel type for termination to wire conductors. Generally it is desirable that these barrel terminals be crimpable to their associated wires. Furthermore, it is also desirable that the terminals be made in a cost effective manner such as by stamping and forming. Having an "open" seam in a barrel, however, can cause problems associated with stress relaxation in that when the terminal is crimped, the forces exerted outwardly along the seam of the crimped terminal may cause the seam to open, thus increasing the electrical resistance through the termination.
U.S. Pat. No. 2,704,358 discloses a contact of the prior art used for power systems having a solid barrel portion, a transition portion and a contact area. The width of the material used in the transition area between contact area and the barrel portion is narrow. The current flowing through this contact area therefore must flow through the narrow transition portion and into the larger body and contact area, thus raising the resistance and thereby the temperature in the transition portion. The very small cross sectional area of the transition portion of the contact terminal in effect may act as a fuse because it can overheat. It is desirable, therefore, to provide a contact terminal or member that will have an essentially constant cross sectional area throughout the length of the terminal.
U.S. Pat. No. 2,535,013 discloses a connector having a crimpable power contact terminal having a solid barrel portion made by brazing the seam of a formed member. Other methods for achieving essentially solid barrel terminals include the use of a separate sleeve disposed over the formed terminal or by use of a machined part. Both of these aforementioned methods increase the number of manufacturing steps and, therefore, the cost of the terminal.
U.S. Pat. No. 2,535,013 discloses a method of crimping barrel type terminals that is designed to be used with a single annular ring such as a solid screw machined part or a formed member having a brazed seam. When the barrel is crimped it is subjected to sufficient pressure that the outer surface undergoes plastic deformation and is essentially locked into place and, therefore, does not stress relax enough to effect the function of the crimped barrel.
U.S application Ser. No. 07/285,681, now abandoned and continued in U.S. patent application Ser. No. 07/376,978 one of the parents of the present application, discloses an electrical contact terminal comprised of a hollow body portion having a plurality of contact sections extending forwardly therefrom, a double layer wire barrel portion and first and second opposing transition portions that extend between the barrel portions and the body portions. The double barrel portion includes inner and outer barrel sections, the first barrel section being nested within the second barrel portion such that a seam of the first barrel section is basically diametrically opposed from the seam of the second barrel section. The double barrel portion, therefore, simulates a continuous annular body that will act in essence as a solid member for crimping without requiring brazing or joining of the seam or a separate solid sleeve member disposed over the seam.
U.S. application Ser. No. 07/359,196, the other parent of the present application discloses a method for making a double barrel portion for a ring-type terminal or other electrical terminal having only a single transition portion between the barrel and the contact portion of the terminal, the double barrel portion being crimpable and acting in essence as a solid member as previously described. It is also desirable, however, to have a ring-type electrical terminal member having a double barrel crimpable portion and a dual transition portion for providing parallel paths for electrical current when the terminal is under load.